Here we investigate antiferromagnetic Eu5In2Sb6, a nonsymmorphic Zintl phase. Our electrical transport data show that Eu5In2Sb6 is remarkably insulating and exhibits an exceptionally large negative magnetoresistance, which is consistent with the presence of magnetic polarons. From ab initio calculations, the paramagnetic state of Eu5In2Sb6 is a topologically nontrivial semimetal within the generalized gradient approximation (GGA), whereas an insulating state with trivial topological indices is obtained using a modified Becke−Johnson potential. Notably, GGA + U calculations suggest that the antiferromagnetic phase of Eu5In2Sb6 may host an axion insulating state. Our results provide important feedback for theories of topological classification and highlight the potential of realizing clean magnetic narrow-gap semiconductors in Zintl materials.

The formulas for magnetic cross sections, I and II , have an incorrect prefactor ͑we thank J.-M. Mignot for pointing this out͒, and the square root in the equation for II on page R14 623 should not be there. Therefore, Eq. ͑3͒ on page R14 622 should be replaced byThe equation on page R14 623 and the two sentences after it should be corrected as follows:Thus II (q)ϭ I (q)/2, and model I and model II cannot be distinguished in the diffraction. However, we prefer model I since a collinear magnetic modulation ͑model II͒ usually squares up with lowering temperature, generating higher order harmonics. The staggered moment at 1.4 K should be 0.75(2) B per Ce, instead of 0.264(4) B per Ce. Other conclusions of the paper are not affected. PHYSICAL REVIEW B 67, 099903͑E͒ ͑2003͒

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We present the results of thermal expansion ␣(T), magnetostriction (H,T), and specific-heat C p (T) measurements made on the heavy-fermion antiferromagnet Ce 2 RhIn 8 . The effects of magnetic order are clearly evident as anomalies in ␣(T) at T N ϭ2.8 K and at T m ϭ1.65 K. C p (T) data indicate that the upper transition corresponds to the onset of long-range antiferromagnetic order while the lower transition involves only a subtle rearrangement of the ordered state. Both C p /T and ␣/T grow with decreasing temperature below 20 K in a manner consistent with Kondo renormalization. Kondo interactions appear to be responsible for the large electronic Grüneisen parameter which extrapolates to ⍀ e Ϸ48 as T→0, while the characteristic Kondo energy is T K Ϸ10 K as determined from the C p /T ratio at T N . Above 20 K ␣(T) is dominated by crystalline-electricfield ͑CEF͒ effects. The data are consistent with a CEF level scheme consisting of excited ⌫ 7(1) and ⌫ 6 doublets lying 71Ϯ6 K and 195Ϯ10 K above a ⌫ 7 (2) ground state. In the paramagnetic state (TϾT N ) the volume magnetostriction follows a simple scaling law, ϰ͓H/(TϩT )͔ 2 . The scaling parameter T ϭ5 K is consistent with the Kondo temperature determined from ␣(T) and C p (T) data. Analysis of (H,T) data also indicates that the magnetic and electronic energy scales associated with the Kondo state in Ce 2 RhIn 8 are equivalent. These thermodynamic data indicate that the physical properties of Ce 2 RhIn 8 result from competition between magnetic exchange, Kondo, and CEF interactions.

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Recently, core-shell nanowires have been proposed as potential electrical connectors for nanoelectronics components. A promising candidate is Mn5Si3 nanowires encapsulated in an oxide shell, due to their low reactivity and...

We report electrical transport measurements on CaMn2Bi2 single crystals under applied pressure. At ambient pressure and high temperatures, CaMn2Bi2 behaves as a single-band semimetal hosting Néel order at TN = 150 K. At low temperatures, multi-band behavior emerges along with an activated behavior typical of degenerate semiconductors. The activation gap is estimated to be ∆ ∼ 20 K. Applied pressure not only favors the antiferromagnetic order at a rate of 0.40(2) K/kbar, but also enhances the activation gap at 20 kbar by about 70 %. This gap enhancement is typical of correlated narrow-gap semiconductors such as FeSi and Ce3Bi4Pt3, and places CaMn2Bi2 as a Mn-based hybridization-gap semiconductor candidate. Ab initio calculations based on the density functional theory are shown to be insufficient to describe the ground state of CaMn2Bi2. arXiv:1907.09984v1 [cond-mat.str-el]

We report a combined study of hydrostatic pressure (P ≤ 25 kbar) and chemical substitution on the magnetic pair-breaking effect in Eu- and Mn-substituted BaFe2As2 single crystals. At ambient pressure, both substitutions suppress the superconducting (SC) transition temperature (Tc) of BaFe2–xCoxAs2 samples slightly under the optimally doped region, indicating the presence of a pair-breaking effect. At low pressures, an increase of Tc is observed for all studied compounds followed by an expected decrease at higher pressures. However, in the Eu dilute system, Tc further increases at higher pressure along with a narrowing of the SC transition, suggesting that a pair-breaking mechanism reminiscent of the Eu Kondo single impurity regime is being suppressed by pressure. Furthermore, Electron Spin Resonance (ESR) measurements indicate the presence of Mn2+ and Eu2+ local moments and the microscopic parameters extracted from the ESR analysis reveal that the Abrikosov–Gor'kov expression for magnetic pair-breaking in a conventional sign-preserving superconducting state cannot describe the observed reduction of Tc.